First thing, if your partition is NTFS, then you can simply put your ISO there, no need to split them with USBUtil. ISO must be put in the right folder ("PS2SMB/DVD/") and with the correct filename, these things have been explained a lot along the various thread.
The port used for sharing is the one of CIFS protocol (or SAMBA on the linux world), which is 445 usually. And you may have nothing to do either on your router or PC, as this port is commonly open by default.
The IP address of your PS2 if your own choice. Run OPL a first time, go to settings, select network settings, enter the right configuration for PC IP, gateway IP, and choose a correct IP for your PS2. Enter the "share" data also, as defined on your PC.
There should not be a problem with password protected share, as you can enter the user/password you want in OPL settings.
It's too late to think that we can worship human emotions
Because we've already evolved into machines in our minds